kubernetes how do I expose pods to things outside of cluster machine?

Question

I read the following kubernetes docs which resulted in the following yaml's to run postgresql & pgadmin in a cluster:

--- pgadmin-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: pgadmin-deployment
spec:
  replicas: 1
  selector:
    matchLabels:
      app: pgadmin-pod
  template:
    metadata:
      labels:
        app: pgadmin-pod
    spec:
      containers:
        - name: pgadmin-container
          image: dpage/pgadmin4
          imagePullPolicy: "IfNotPresent"
          ports:
            - containerPort: 80
          env:
            - name: PGADMIN_DEFAULT_EMAIL
              value: email@example.com
            - name: PGADMIN_DEFAULT_PASSWORD
              value: password

--- pgadmin-service.yaml
apiVersion: v1
kind: Service
metadata:
  name: pgadmin-service
spec:
  type: NodePort
  ports:
    - port: 30000
      targetPort: 80
  selector:
    app: pgadmin-pod

--- postgres-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: postgres-deployment
spec:
  replicas: 1
  selector:
    matchLabels:
      app: postgres-pod
  template:
    metadata:
      labels:
        app: postgres-pod
    spec:
      containers:
        - name: postgres-container
          image: postgres:9.6-alpine
          imagePullPolicy: "IfNotPresent"
          ports:
            - containerPort: 5432
          env:
            - name: POSTGRES_DB
              value: database
            - name: POSTGRES_PASSWORD
              value: password
            - name: POSTGRES_USER
              value: username
          volumeMounts:
            - mountPath: /var/lib/postgresql/data
              name: postgrepvc
      volumes:
        - name: postgrepvc
          persistentVolumeClaim:
            claimName: postgres-pv-claim

--- postgres-service.yaml
apiVersion: v1
kind: Service
metadata:
  name: postgres-service
spec:
  type: NodePort
  ports:
    - port: 30001
      targetPort: 5432
  selector:
    app: postgres-pod

--- postgres-storage.yaml
postgres-storage.yaml
kind: PersistentVolume
apiVersion: v1
metadata:
  name: postgres-pv-volume
  labels:
    type: local
    app: postgres
spec:
  storageClassName: manual
  capacity:
    storage: 5Gi
  accessModes:
    - ReadWriteMany
  hostPath:
    path: "/mnt/data"
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: postgres-pv-claim
  labels:
    app: postgres
spec:
  storageClassName: manual
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 5Gi

I then run the following command kubectl create -f./ which results in the following: kubernetes pods / svc's

Then I try to access pgAdmin on 10.43.225.170:30000 from outside of the cluster, but I get "10.43.225.170 took too long to respond." no matter what I try.

So how do I expose pgAdmin & postgress to the outside world, and is there a way to give them static ip's so I don't have to update ip's in connection strings each time I re-deploy on kubernetes, or do I have to use statefulset for this?

Answer 1

---

Problems here

1. you are trying to reach node internal ip 10.43.225.170 instead of external one.
2. nodePort service configured incorrectly. In addition you are trying to call incorrect port

---

You haven't specified what platform you use. I'm using GKE, so in my case its easier because I have external IP's automatically assigned during cluster node creation. But I had to manually create ingress firewall rule to allow access from outside to nodes and required ports (30000,30001)

In any case, to be able to use nodePort - you should have external IP address assigned to one of the nodes in cluster and a Firewall rule that allows ingress traffic to that port

---

Going next. You are trying to call <NodeIP>:spec.ports[*].port .

As per Type NodePort documentation :

Service is visible as <NodeIP>:spec.ports[*].nodePort

You need explicitly specify nodePort

---

I have changed a bit your deployment, can access pgAdmin after deploying it and opening corresponding ports in firewall.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: pgadmin-deployment
spec:
  replicas: 1
  selector:
    matchLabels:
      app: pgadmin-pod
  template:
    metadata:
      labels:
        app: pgadmin-pod
    spec:
      containers:
        - name: pgadmin-container
          image: dpage/pgadmin4
          imagePullPolicy: "IfNotPresent"
          ports:
            - containerPort: 80
          env:
            - name: PGADMIN_DEFAULT_EMAIL
              value: email@example.com
            - name: PGADMIN_DEFAULT_PASSWORD
              value: password

---
apiVersion: v1
kind: Service
metadata:
  name: pgadmin-service
spec:
  type: NodePort
  ports:
    - nodePort: 30000
      targetPort: 80
      port: 80
  selector:
    app: pgadmin-pod

--- postgres-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: postgres-deployment
spec:
  replicas: 1
  selector:
    matchLabels:
      app: postgres-pod
  template:
    metadata:
      labels:
        app: postgres-pod
    spec:
      containers:
        - name: postgres-container
          image: postgres:9.6-alpine
          imagePullPolicy: "IfNotPresent"
          ports:
            - containerPort: 5432
          env:
            - name: POSTGRES_DB
              value: database
            - name: POSTGRES_PASSWORD
              value: password
            - name: POSTGRES_USER
              value: username
          volumeMounts:
            - mountPath: /var/lib/postgresql/data
              name: postgrepvc
      volumes:
        - name: postgrepvc
          persistentVolumeClaim:
            claimName: postgres-pv-claim

---
apiVersion: v1
kind: Service
metadata:
  name: postgres-service
spec:
  type: NodePort
  ports:
    - nodePort: 30001
      targetPort: 5432
      port: 5432
  selector:
    app: postgres-pod

---
kind: PersistentVolume
apiVersion: v1
metadata:
  name: postgres-pv-volume
  labels:
    type: local
    app: postgres
spec:
  storageClassName: manual
  capacity:
    storage: 5Gi
  accessModes:
    - ReadWriteMany
  hostPath:
    path: "/mnt/data"
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: postgres-pv-claim
  labels:
    app: postgres
spec:
  storageClassName: manual
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 5Gi

Check:

kubectl apply -f pg_my.yaml
deployment.apps/pgadmin-deployment created
service/pgadmin-service created
service/postgres-service created
persistentvolume/postgres-pv-volume created
persistentvolumeclaim/postgres-pv-claim created


#In my case I take node external ip from any node from `kubectl get nodes -o wide` output:
NAME                                       STATUS   ROLES    AGE   VERSION            INTERNAL-IP   EXTERNAL-IP
gke-cluster-1-default-pool-*******-*****   Ready    <none>   20d   v1.18.16-gke.502   10.186.0.7    *.*.*.*

curl *.*.*.*:30000
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
<title>Redirecting...</title>
<h1>Redirecting...</h1>
<p>You should be redirected automatically to target URL: <a href="/login?next=%2F">/login?next=%2F</a>.